1. Field of the Invention
This invention relates to a toner used in image forming processes such as electrophotography, electrostatic printing and toner jet recording.
2. Related Background Art
Conventionally, it is known to incorporate a toner with an alcohol component in order to improve low-temperature fixing performance and high-temperature anti-offsetting properties of the toner.
Japanese Patent Laid-open Applications Nos. S63-113558, S63-188158, H02-134648, H04-097162, H04-097163 and so forth discloses techniques in which toners are incorporated with alcohol components.
Incorporation of toners with waxes having such alcohol components may bring out the effect of improving low-temperature fixing performance and high-temperature anti-offsetting properties of the toners, but, when used in a severe environment such as a high-temperature and high-humidity environment over a long period of time, tends to accelerate deterioration of toners to make their developing performance poor in some cases.
Japanese Patent Laid-open Application No. 2001-343781 also discloses a toner containing a hydrocarbon wax having a hydroxyl value (HV) of 5 to 150 mgKOH/g, an ester value (EV) of 1 to 50 mgKOH/g and HV>EV.
Japanese Patent Laid-open Application No. 2000-267347 further discloses a wax for electrophotographic toners which is an alcohol type wax having a hydroxyl value of 50 to 90 mgKOH/g, obtained by subjecting any of a petroleum wax, an α-olefin wax having a double bond at its terminal and Fischer-Tropsch wax to air oxidation in the presence of boric acid.
Incorporation of toners with such waxes having a hydroxyl group enables improvement in low-temperature fixing performance and high-temperature anti-offsetting properties and also achievement of superior developing performance. However, in a situation where the internal temperature of a copying machine or printer has come higher as in the case of double-side printing performed continuously in a high-temperature environment, the toner may melt-stick to a photosensitive member to cause image defects such as white dots or a cleaning blade coming into contact with the photosensitive member may turn up to cause faulty cleaning. In order to resolve such problems, it is necessary to lessen the content of the wax having a hydroxyl group, and this makes the toner less effectively improved in low-temperature fixing performance and high-temperature anti-offsetting properties.